There are three specific aims of this project. The first is to examine 12-0-tetradecanoylphorbol-13-acetate (TPA)-treated leukemic cells for changes in surface antigen profile and proliferative capacity. Cells will be freshly obtained from patients with ANLL, ALL, CLL, CML in blast crisis and hairy cell leukemia. They will be tested for ability to bind a number of monoclonal and conventionally derived antibodies to establish a baseline antigen "profile," then allowed to incubate with TPA and retested. Their proliferative capacity will be tested before and after incubation as well. The Ortho Spectrum III Cytofluorograf will be used for all analyses. We will determine whether TPA treatment is helpful in inducing maturation in vitro, classifying previously unclassifiable cells and decreasing leukemic cell proliferation. Second, we have investigated the modulation of development of normal granulocyte/monocyte colony-forming cells by TPA, retinoic acid and prostaglandin E1. We have evidence suggesting that there are different mechanisms that mediate the inhibition of monocyte colony development produced both by retinoic acid and PGE1. Third, we will assess whether activated helper T cells combined with monocytes in liquid culture can produce colony stimulating activity (CSA). We will combine populations of monocyte subsets and T-cell subsets purified by adherence procedures, E-rosetting and T-cell subset fractionations using a sepharose column. We have determined that T cells produce CSA in the absence of macrophages, and that macrophages alone produce little CSA. Either helper or unsorted T cells combined with macrophages support CAS production, while suppressor T cells do not.